Coal ash upside? State, Duke seek beneficial uses

Robert Mensah-Biney, Ph. D., holds some coal ash samples that are being explored in various applications and products including building materials at the Minerals Research Laboratory at 180 Coxe Ave. in Asheville on Jan. 24.(Photo: William Woody / wwoody@citizen-times.com)Buy Photo

Advocates of coal ash recycling say a recent federal ruling that determined the waste is not hazardous has paved the way for continued use of coal ash in concrete and other industries.

Critics of that Environmental Protection Agency decision in December blasted the agency for what they called lax regulation of a toxic byproduct, but industry experts and researchers are trying to cement the future of coal ash as a business able to grow in the Tar Heel state, using coal ash generated by Duke Energy plants.

Coal ash use and disposal is being reviewed in the N.C. Coal Ash Management Commission and in an ad hoc committee of the Environmental Management Commission called Beneficial Reuse of Coal Ash, under the state Department of Natural Resources.

Both have requested deadline extensions for expected reports. The Beneficial Reuse of Coal Ash committee's report is expected in April; the Management Commission has not given a timeframe.

Duke Energy has asked researchers and businesses to submit market analyses of coal ash uses in the state by Feb. 20, and Duke officials believe they can recycle all coal ash being produced, but they have declined to offer a timeframe for reaching that goal.

"The fact is, as long as we're burning coal, we're going to have coal ash, and it makes a lot more sense to recycle the material than send it off for disposal," said Thomas Adams, executive director of the American Coal Ash Association.

Architects and engineers would have abandoned coal ash in construction projects had the EPA given it hazardous designation in testimony last month in Washington, D.C., he said.

Waste from the burning of coal has long been used in construction applications, though it often requires additional processing. Lightweight fly ash is lauded for strengthening Portland cement, while heavier bottom ash can be substituted as an aggregate in the place of sand and gravel. A byproduct of scrubbers on smokestacks, synthetic gypsum, is often used to make drywall.

Use of those products dropped off from a nationwide peak of 60.6 million tons in 2008, according to the coal ash association. That same year, when construction slumped into a recession, the Kingston, Tennessee, spill dumped a billion gallons of sludge into that area, underscoring the magnitude of the coal ash disposal problem.

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Hamid Akbari conducts pressure tests on some coal ash samples, which are being explored in various applications and products including building materials at the Minerals Research Laboratory.(Photo: William Woody / wwoody@citizen-times.com)

Duke is recycling 43 percent of coal ash produced in day-to-day operations, said spokeswoman Catherine Butler, and the company will be examining other opportunities for coal ash use in North Carolina through submitted proposals.

Last year, Duke produced about 2.8 million tons of coal ash.

One method the utility is examining is used by The SEFA Group, a company that processes and sells coal ash. That company has contracted with South Carolina utility Santee Cooper and is opening a new facility in Georgetown, South Carolina, that will be able to process wet coal ash. That plant joins two other SEFA facilities able to make pond ash usable, one located in Maryland and another that is contracted with South Carolina Electric & Gas Co.

For coal ash to be viable in construction, it generally needs further processing to remove carbon and other organic material. Complicating that is the quality of the ash. Factors like burn temperatures of the coal affect purity, and coal ash left sitting in ponds is sapped of qualities that make it desirable for building.

To process ash for reuse requires foresight, a long-term commitment and a decades-long contract so a company can recoup high capital costs, said Jimmy Knowles, SEFA vice president of research and market development.

"We see a complicated puzzle," Knowles said. "There are lots of individual puzzle pieces that have to be arranged and we would like to be one of those puzzle pieces."

He credited Santee Cooper for its negotiations with Frank Holleman, an attorney with the Southern Environmental Law Center who has filed multiple federal lawsuits against Duke in North Carolina on behalf of groups demanding cleanup of coal ash ponds. Duke has 152 million tons of coal ash stored in basins and storage areas at 14 sites across the state.

As a result of those discussions, Knowles said, Santee Cooper was granted a longer timeline to manage its coal ash ponds, avoiding litigation.

"Santee Cooper believed in coal ash benefication," he said, using a company term for making coal ash suitable for use. "But for Duke, their preference has been fiduciary. It's always cheaper in the short term to put coal ash in a hole in the ground. It's the lower cost option."

The law center's primary goal has been to see coal ash excavated from unlined, leaking pits near waterways, Holleman said, and his experience in North and South Carolina to accomplish that goal diverged wildly.

"Once we forced the issue with citizen litigation and the public became aware of the problem, Santee Cooper, to its credit, re-examined what it was doing and agreed to clean up the site," Holleman said. "This change of course led to an extensive recycling program that has produced jobs for the local economy and is making the community and the river safer every day."

Where Santee Cooper was open to negotiation that ended litigation, Duke has yet to settle a case, he said.

In North Carolina, Duke is facing a 2019 deadline to shutter four coal ash ponds, including the Lake Julian site in Asheville. About 5 million tons of that ash is being used as structural fill at the Asheville Regional Airport. The utility must safely close all other basins by 2029.

In the longer term, Robert Mensah-Biney, of the Asheville-based N.C. State University Minerals Research Laboratory, said his agency also is applying to Duke's request for proposals.

“The fact is, as long as we're burning coal, we're going to have coal ash, and it makes a lot more sense to recycle the material than send it off for disposal.”

Thomas Adams, executive director of the American Coal Ash Association

He would like to see funding for a technology it has worked on in the lab that replaces Portland cement with coal ash in concrete applications.

Mensah-Biney headed a consortium that ended in 2007 that focused on using sludge from hog waste, and later slurries produced by paper mills, in combination with coal ash to create a lightweight aggregate.

The group included Duke and Progress Energy, but it ended as the economy tanked, Mensah-Biney said.

They developed a viable business plan for the aggregate, he said, and the lab has the ability to set up a mini-factory to test real-world conditions.

When support ended, Mensah-Biney packed away his aggregate samples and moved on to other projects. With the call for coal ash solutions, he's pulled them out again, created new aggregates and is again examining different ways to use coal ash.

"We do the work and propose the solution, but how they use the work to make economic solutions is out of our hands," he said. "If you are making electricity for the population with coal, you are going to have a waste product. Now they have to start thinking about it. That is the bottom line."

One method Duke is examining is used by the SEFA Group, which is contracting with a South Carolina utility and opening a new facility in Georgetown, South Carolina, to process wet coal ash. Two other SEFA facilities make pond ash usable.

The quality of coal ash determines whether it can be used in construction. Several factors complicate quality:

Burn temperature of the coal affects purity.

Coal ash left sitting in ponds saps it of desirable qualities.

What are labs working toward?

Robert Mensah-Biney, of the Asheville-based N.C. State University Minerals Research Laboratory, wants to see funding for a technology that replaces Portland cement with coal ash in concrete applications.

His agency is applying to Duke's request for proposals of coal ash uses in the state. Researchers and businesses are asked to submit market analyses of coal ash uses in the state by Feb. 20.